Laminar flow devices are devices which have been developed for the purpose of providing constant volume flow in apparatus which require the latter for proper operation. As the name suggests, they are based on the characteristic of fully developed, steady laminar flow of fluid through a passage wherein the actual volume rate of flow is linearly proportional to the pressure differential per unit length of the passage.
Heretofore, laminar flow devices have taken the form of a multiplicity of small diameter tubes of equal length disposed in parallel relation in an appropriate fluid passage. A typical device would consist of approximately 23 tubes. It can be shown that, for a given flow rate, the length of the tubes is proportional to the fourth power of the inside diameter of the tubes. Accordingly, in order to maintain the device as short and compact as possible, it is necessary to use very small diameter tubes. The smallest readily available brass tubes have an inside diameter of 0.02 inches. In order to obtain fully developed, steady laminar fow in the tubes, the ratio of the length to inside diameter must be at least 200 and thus the length of the tubes must be at least 4 inches. It has been found that not only is the above minimum length excessively long, the task of assembling the large number of tubes in position requires excessive skill and this increases manufacturing cost. There is a need therefore for a more compact and easily manufactured and assembled laminar flow device.